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THINK! How do you think the world works? How do you translate “how the world works” into: design (choice of subjects) measurement model (diagram, algebra) data (expectations for statistics) analysis (code, decision) OpenMx can help you do the nuts and bolts.

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Now Try It Yourself! Work out expected covariances and correlations For different values of b (symmetric) Use positive and negative values of b For models with and without A Try to predict your answers Summarize the principal implications of social interaction for the data Under what circumstances are you likely/unlikely to detect interactions?

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Now…Think about other worlds What would you expect for singletons What do you think would happen in larger sibships (3,4…siblings)? How would you model the process? TRY IT!!!!